The present invention relates in general to tooling for use in banding articles, and more particularly, to a banding apparatus that heat seals plastic strapping together, using a heating element.
Use of thermoplastic strapping to band an article or set of articles together is widely known. As is known, the thermoplastic strap is disposed about the article or articles, tensioned and then two portions of the strap are melted together. Usually, the banded portion of the strap is a portion of a larger roll of thermoplastic strapping. In such a case, the bonding is performed between the free end of the roll and a portion of the strap adjacent a cutting point. Thus, the sealing operation occurs between a first and second end of the plastic strapping. In all cases, the plastic strapping is required to be tensioned. This tensioning may be accomplished through the use of an integrated or separate tensioning mechanism.
The melting and affixation operations has been conventionally performed by one of two types of approaches: friction-weld melting and thermal heat-blade heating. A "friction-weld" apparatus works by rubbing the two strap ends together at relatively high speeds to heat the strapping by friction. Cheung, U.S. Pat. No. RE. 31,353; Schaub et al., U.S. Pat. No. 3,058,513; Hull, U.S. Pat. No. 3,062,695; Gilmore, U.S. Pat. No. 3,709,758; Styner et al., U.S. Pat. No. 3,984,278; Cheung, U.S. Pat. No. 4,062,278; Lehman, U.S. Pat. No. 4,096,019; Wehr, U.S. Pat. No. 4,227,949; Toth, U.S. Pat. No. 4,377,428; Wehr, U.S. Pat. No. 4,450,032; Kobiella, U.S. Pat. No. 4,479,834; Fischer, U.S. Pat. No. 4,820,363; Niedrig, U.S. Pat. No. 4,871,414; Cheung et al., U.S. Pat. No. 4,952,271; Kagi, U.S. Pat. No. 5,058,365; Kobiella, U.S. Pat. No. 5,306,383; Kobiella, U.S. Pat. No. 5,350,472; and Harada, U.S. Pat. No. 5,476,569 are all representative of this type of "friction-weld" apparatus.
Thermal heating apparatuses work by bringing the strap ends into operable contact with a heated element, such as a knife or a blade. Bona, U.S. Pat. No. 2,582,581; Briscoe, U.S. Pat. No. 3,043,210; Nakano, U.S. Pat. No. 3,438,833; Osmalov, U.S. Pat. No. 3,542,627; Ross et al., U.S. Pat. No. 3,563,833; Takami, U.S. Pat. No. 3,755,045; Sato et al., U.S. Pat. No. 3,749,622; Tsuda, U.S. Pat. No. 3,767,512; Fuchs et al., U.S. Pat. No. 3,770,540; Wehr, U.S. Pat. No. 3,783,079; Takahashi, U.S. Pat. No. 3,863,557; Spears et al., U.S. Pat. No. 3,929,541; Burgheimer, U.S. Pat. No. 3,944,454; Wyse, U.S. Pat. No. 3,962,017; Andrews, U.S. Pat. No. 3,986,919; Takami, U.S. Pat. No. 4,016,023; Kyts, U.S. Pat. No. 4,063,985; Johnson, III et al., U.S. Pat. No. 4,157,274; Gould, U.S. Pat. No. 4,158,711; Pennington, U.S. Pat. No. 4,240,855; Kyts, U.S. Pat. No. 4,240,865; Mossell et al., U.S. Pat. No. 4,288,270; Struve, U.S. Pat. No. 4,445,955; Ford, U.S. Pat. No. 4,504,353; Ford et al., U.S. Pat. No. 4,595,433; Kobiella, U.S. Pat. No. 4,661,185; Forthmann, U.S. Pat. No. 4,743,333; Cheung et al., U.S. Pat. No. 4,776,905; Emenaker et al., U.S. Pat. No. 5,514,237; Canadian Patent No. 700,336; UK Patent No. 929,803; UK Patent No. 1,039,898; UK Patent No. 1,045,279; UK Patent No. 1,193,618; and UK Patent Application No. 2,082,500, in various environments disclose this type of apparatus.
There are various disadvantages associated with the apparatuses disclosed in these patent references. Some units are not portable, thus significantly limiting their usefulness in banding various articles. Some units are overly complex and bulky. Further, several manual units require ultimate end-user control of the timing and sequencing. Yet other units rely on pneumatic pressure to control operation timing, thus, requiring a constant pressure source. Yet other units require microprocessor control and sequencing, which increases the expense of those units. Still further, many units fail to provide safety enclosures to protect users from the high-temperature heating elements necessary to melt the thermoplastic strapping. Many prior units further require both strap ends to be tensioned prior to the sealing operation.
It is an object of the present invention to avoid these problems. In particular, it is an object of the present invention to provide a rotationally actuated heat sealing unit toward providing a less expensive, more reliable apparatus. Rotational actuation facilitates an even, continuous application of rotational energy; imparting such an even operation to the heat sealing operations, themselves. These operations may be driven by a small motor or manually with the same even, continuous application.
It is an associated object of the present invention to require only a uni-directional motion for end-user actuation of the heat sealing apparatus toward avoiding variations in heat sealing due to differences in end-user's manual dexterity, strength, time-interval and abilities to understand otherwise complex instructions. Similarly, it is an associated object of the present invention to require only a unidirecional motion for motorized actuation of the heat sealing apparatus toward avoiding the need for a bidirectional motor or linkage, and variations in torque and speed between opposing directions in bidirectional motors.
It is a further associated object of the present invention to control the heat sealing apparatus to fully utilize the various rotational components of the apparatus toward ensuring proper time allocation amongst the plurality of step conducted by the apparatus to achieve heat sealing of the plastic strapping.
It is a further object of the present invention to provide a heat sealing apparatus that is easy to operate, thus, requiring little training to ensure consistent desirable operation of the unit.
It is yet another object of the present invention to provide a portable unit to facilitate carrying and placement of the unit in various locations.
In is an additional object of the present invention to provide a reliable heating-element based heat sealing apparatus, that provides various protections to the end-user to prevent inadvertent injury.
These and other objects of the present invention will become apparent in light of the attached specification, drawings and claims.